Record the stock concentration, target concentration, final volume, dilution factor, reaction count, overage, and units. Missing units are one of the most common causes of repeated calculation mistakes.
Assumptions
Assumptions should be visible. Examples include molecular weight, DNA length, extinction coefficient, viable fraction, rotor radius, and expected reaction count.
Versioning
If a calculation is reused, record the date and any change in sample quality, reagent concentration, or protocol version. Old values can become wrong after cleanup, evaporation, thawing, or stock replacement.
Practical record format
- Purpose of the calculation.
- Input values with units.
- Assumptions and source.
- Final table or setup volume.
- Controls and replicate count.
- Who reviewed or used the result.
Why this matters
Documented calculations make experiments easier to repeat, easier to review, and easier to troubleshoot when the observed result does not match expectation.